Exercise treadmill

ABSTRACT

A treadmill has a front or rear set of pulleys and a looped running belt. The pulleys rotate with the movement of the belt, e.g., when a user walks, jogs, or runs on the treadmill. The pulleys are mounted on a rotating roller tube so that the roller tube rotates with the pulleys. The roller tube is mounted on a stationary shaft using bearings on each side and a one-way device that allows the pulleys to rotate in one direction. The rotation direction corresponds to the movement of the top of the belt from the front to the rear of the treadmill. The one-way device prevents the pulleys from rotating in the opposite direction, preventing the top of the belt from moving from the rear of the treadmill to the front. The one-way device may be a sprag clutch. The treadmill may be a motor-less, curved treadmill.

RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 18/095,792 filed 11 Jan. 2023, which is a continuation of U.S.patent application Ser. No. 16/906,195 filed 19 Jun. 2020, which is acontinuation of U.S. patent application Ser. No. 15/833,991 filed 6 Dec.2017, each of which is incorporated herein by reference in its entirety.

BACKGROUND Field of the Invention

This document generally relates to the field of exercise treadmills andtechniques for mounting components to allow rotation of pulleys in onedirection and to prevent rotation of pulleys in the opposite direction.This document also relates to facilitating appropriate hand placement ontreadmill handlebars and corresponding foot placement on treadmill belt.

Related Art

A typical treadmill has a looped running belt supported on each end by aroller assembly that rotates to allow a person (the treadmill user) torun, jog, or walk. There are motorized treadmills as well as manualtreadmills. Treadmills, particularly of the manual (i.e., non-motorized)type, may be curved, to allow variation in exercise intensity. Manualtreadmills preferably do not allow significant movement of the loopedbelt in the reverse direction, i.e., movement of the top surface fromback to front. Preventing movement in the reverse direction may beachieved by installing a one-way clutch (a k a one-way bearing) on oneof the roller assemblies.

A need in the art exist for new and better techniques for preventingreverse direction movement of looped belts on treadmills. A need in theart also exists for new and better designs of roller assemblies thatallow rotation in one direction and prevent significant rotation in theopposite direction. A need in the art exists for techniques that helpthe user to coordinate treadmill handlebars gripping locations with thedesired intensity and/or step length.

SUMMARY

Embodiments, variants, and examples described in this document aredirected to apparatus and methods that may satisfy one or more of theabove described needs and/or other needs. Select examples showtreadmills with stationary shaft and rotating roller.

In an embodiment, a treadmill includes a frame. The treadmill alsoincludes a looped running belt. The treadmill additionally includes afirst roller assembly that has a first roller tube, a first rotatingpulley and a second rotating pulley mounted on the first roller tube sothat the first and second rotating pulleys rotate together with thefirst roller tube, a first shaft fixedly mounted on the frame so thatthe first shaft does not rotate with the first and second rotatingpulleys and the first roller tube, a first load bearing, a second loadbearing, and a one-way device. The treadmill further includes a secondroller assembly mounted on the frame. The looped running belt issupported by the second roller assembly, the first rotating pulley, andthe second rotating pulley, so that the first and second rotatingpulleys rotate with movement of the looped running belt. The first loadbearing and the second load bearing are disposed between the firstroller tube and the first shaft, so that the first roller tube and thefirst and second pulleys can rotate around the first shaft. The one-waydevice comprises an inner ring and an outer ring, the inner ring beingfixedly coupled to the first shaft not to rotate on the first shaft, theouter ring is fixedly coupled to the roller tube to allow the rollertube to rotate in a first direction around the first shaft and toprevent the roller tube from rotating around the first shaft in a seconddirection that is opposite to the first direction, the first and seconddirections being such that top surface of the looped running belt canmove from front of the treadmill to rear of the treadmill and the topsurface is prevented from moving from the rear of the treadmill to thefront of the treadmill.

In an embodiment, a treadmill includes a frame; a looped running belt;and a first roller assembly comprising a first rotating pulley and asecond rotating pulley, a second roller assembly comprising a thirdrotating pulley and a fourth rotating pulley, the first roller assemblyand the second roller assembly being mounted on the frame, the loopedrunning belt being supported by the first rotating pulley, the secondrotating pulley, the third rotating pulley, and the fourth rotatingpulley. The first roller assembly also comprises means for allowing topsurface of the running belt to move from front to rear of the treadmilland for preventing the top surface from moving from rear to front of thetreadmill.

These and other features and aspects of selected embodiments, variants,and examples consistent with the present disclosure will be betterunderstood with reference to the following description, drawings, andappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating selected components andfeatures of a curved treadmill, in accordance with selected aspects ofthis disclosure;

FIG. 2 and FIG. 3 are perspective views of the treadmill of FIG. 1 withside shrouds removed;

FIG. 4 and FIG. 5 are perspective views of the treadmill of FIG. 1 withthe shrouds and the looped running belt removed;

FIG. 6 is a side plan view of the treadmill of FIG. 1 with the shroudsand the looped running belt removed;

FIG. 7 is a sectional view of the front roller assembly of the treadmillof FIG. 1 ;

FIG. 8 is another perspective view of the treadmill of FIG. 1 with anumber of components removed; and

FIG. 9 is a perspective view of a treadmill with color-coded verticalhand grip positions and corresponding color coded front foot placementpositions.

DETAILED DESCRIPTION

The words “embodiment,” “variant,” “example,” and similar words andexpressions as used herein refer to a particular apparatus, process, orarticle of manufacture, and not necessarily to the same apparatus,process, or article of manufacture. Thus, “one embodiment” (or a similarexpression) used in one place or context may refer to a particularapparatus, process, or article of manufacture; the same or a similarexpression in a different place or context may refer to a differentapparatus, process, or article of manufacture. The expression“alternative embodiment” and similar words and phrases are used toindicate one of a number of different possible embodiments, variants, orexamples. The number of possible embodiments, variants, or examples isnot necessarily limited to two or any other quantity. Characterizationof an item as “exemplary” means that the item is used as an example.Such characterization does not necessarily mean that the embodiment,variant, or example is a preferred one; the embodiment, variant, orexample may but need not be a currently preferred embodiment, variant,or example. All embodiments, variants, and examples are described forillustration purposes and do not necessarily strictly limit theinvention(s) disclosed.

A “one-way device” refers to a one-way sprocket or a one-way clutch (a ka “one-way clutch bearing” or “one-way bearing”) or analogous type ofratcheting mechanism that allows rotation in one direction only. A“one-way clutch” means a sprag clutch, a rolling element that allowsrotation in one direction but locks up to prevent movement in the otherdirection. A sprag clutch typically employs spring-loaded sprag rollersthat allow one element to freewheel around another element, until therotation direction is reversed.

A curved treadmill allows a user to walk/jog/run on a curved surface,for example, a surface that varies the incline from substantially flathorizontal (zero degrees) or even a slight negative setting (decline,say a decline of less than 10 degrees) to an incline that providessubstantial increase in the exercise intensity, for example, 8-30degrees from horizontal.

Some definitions have been explicitly provided above. Other and furtherexplicit and implicit definitions and clarifications of definitions maybe found throughout this document.

FIG. 1 is a perspective view illustrating selected components of acurved treadmill 100. In this example, the treadmill 100 is a motorlesstreadmill. The treadmill 100 includes handlebars 105 attached tohandlebar mounts 110A/110B, electronic monitor/controller module 115attached substantially at the center of the handlebars 105, a loopedbelt 120 made of a large number (e.g., 40-100) of individual slats 125,and protective shrouds 130A and 130B on the sides of the treadmill. Stepboards 122A and 122B on the tops of the shrouds 130A and 130B,respectively, provide traction surfaces that the user can step on whenmounting and dismounting from the treadmill 100. A raising bar 155 atthe rear of the treadmill 100 allows the user to lift the rear of thetreadmill 100 off the floor and move the treadmill 100 on its frontwheels.

FIG. 2 and FIG. 3 are perspective views of the treadmill 100 with theshrouds 130A and 130B removed. As can be seen in these Figures, thetreadmill 100 further includes a longitudinal frame bar 135A on the leftside; another longitudinal frame bar 135B (not shown in these Figures)is analogous to the frame bar 135A mutatis mutandis and is disposed in asimilar position on the right side of the treadmill 100. (“Left” and“right” have been arbitrarily selected with reference to a user as theuser would be walking/jogging/running forward on the treadmill 100.)Vertical supports 138A, 140A, and 142A support the curved assembly onthe left side. Again, analogous arrangement mutatis mutandis is on theright side of the treadmill 100. The treadmill 100 rests on front wheels145A and 145B, and on adjustable non-wheeled supports in the rear 150A(on the left side) and 150B (on the right side, shown in FIG. 4 ).

FIG. 4 and FIG. 5 are perspective views of the treadmill 100 with theshrouds 130A/130B and the belt 120 removed, providing a better view offrame cross-members 160A/160B/160C, which can be seen extending betweenthe longitudinal frame bars 135A/135B. These Figures also show portionsof a multi-component front roller assembly 170 and a multi-componentrear roller assembly 190.

FIG. 6 is a side view of the treadmill 100.

FIG. 7 is a sectional view of the front roller assembly 170, along thesection AA (which is shown in FIG. 6 ).

At the center of the front roller assembly is a shaft 172. Through holes174A and 174B on the ends of the shaft 172 receive bolts that secure theshaft 172 to the frame of the treadmill 100. Note that the shaft 172 isnot intended to rotate relative to the frame in response to the movementof the belt 120. Oval indentation 176 in the surface of the shaft 172 isdesigned to receive a key that can be press-fit into the indentation176; the key is intended to protrude from the shaft 172 and to fit intoa corresponding bearing keyway on the surface of the inner ring of aone-way clutch bearing 178, fixing (preventing rotation of) the innerring of the one-way clutch 178 relative to the shaft 172. It is possibleto manufacture the shaft with the key being integral to the shaft.

A roller tube 180 surrounds the shaft 172. It may be machined frommetal, e.g., steel or iron. On the left side, a cylindrical metal insert181A is press-fitted inside the roller tube 180. The one-way clutch 178is press-fitted inside the insert 181A. The insert 181A also receives aconventional (not one-way) load bearing 182A. The bearing 182A may alsobe press-fitted into the insert 181A. A pulley 183A is fixedly attached(e.g., glued) onto the roller tube 180.

On the right side of the assembly 170, another pulley 183B is fixedlyattached (e.g., glued) onto the roller tube 180, and a secondcylindrical metal insert 181B is press-fitted inside the roller tube180. The pulleys 183A/B may be injection molded plastic. The secondmetal insert 181B receives a second conventional load bearing 182B,which may be press-fitted inside the insert 181B. Note that the secondinsert 181B may be (but need not be) shorter than the first insert 181A,because there is no need for a second one-way clutch. (Of course, asecond one-way clutch may also be employed on the right side.)

The pulleys 183A and 183B support the belt 120, which on its inside hastwo sets of guiding protrusions running along the belt 120. The guidingprotrusions are set at such a width that each fits between the flangesof its corresponding pulley 183A or 183B. As can be seen in FIG. 8 ,which is another perspective view of the treadmill 100 with the shrouds130A/B and the belt 120 removed, there are rows 185A and 185B ofsupporting/guiding bearings interspersed with guiding pulleys, along thesides of the step boards 122A/122B of the treadmill 100. The bearingsand pulleys of the rows 185A/B support the belt 120 and, together withthe flanges of the pulleys 183A/B guide (prevent excessive side slippageof) the belt 120. The guiding protrusions of the belt 120 fit betweenthe flanges of the guiding pulleys of the rows 185A/B.

In operation, the roller tube 180 would be free to rotate around theshaft 172 in either direction, but for the presence of the one-wayclutch 178. The one-way clutch 178 allows rotation only in onedirection. Viewed from the left side of the treadmill 100, the rollertube 180 and the pulleys 183A and 183B can rotate clockwise, to allowthe top surface of the belt 120 to move from the front to the rear ofthe treadmill 100 as the user walks/jogs/runs forward on the belt 120.

The rear roller assembly 190 may be quite similar to the front rollerassembly 170. The assembly 190, however, need not include a one-wayclutch or another one-way device, because the belt 120 should not havesignificant movement in the undesirable direction due to the one-wayclutch 178 on the front roller assembly 170. The rear roller assembly190 may also differ significantly from the front roller assembly 170;for example, the rear roller assembly may have pulleys mounted on arotating shaft supported by a pair of bearings mounted in the frame ofthe treadmill.

In embodiments, another type of one-way device is employed in the steadof the one-way clutch bearing 178. In embodiments, each side of the rearroller assembly 190 is analogous to the right side of the front rollerassembly 170. In embodiments, there is a one-way device on one end orboth ends of the rear roller assembly 190. In embodiments, a one-wayclutch (or another one-way device) is installed on one, two, three, orall four ends of the roller assemblies 170 and/or 190. In embodiments,the treadmill is a motorless treadmill, while in other embodiments thetreadmill is motorized.

FIG. 9 is a perspective view of a treadmill 900 with color-codedvertical hand grip positions and corresponding color-coded front footplacement positions. The treadmill 900 (which is curved in the shownembodiment) includes a looped running belt 920, handlebars 905,handlebar mounts 910A/910B, shrouds 930A/930B, and electronicmonitor/controller module 915. The treadmill 900 also includes verticalgrips 999A and 999B, which may be fastened in different positions on thehandlebars 905. The vertical grips 999A/B may be fastened in differentpositions using, for example, locking screws. In the shown embodiment,there are three positions on each side for the vertical grips. The threepairs of handlebar positions are marked with bands or LEDs of differentcolors. For example, bands 992A and 992B may be yellow; bands 993A and993B may be orange; and bands 994A and 994B may be red. Correspondingcolor strips are disposed on each side of the belt 920. For example,color strips 998A and 998B may be yellow; color strips 997A and 997B maybe may be orange; and color strips 996A and 996B may be red. The colorstrips may be glued, e.g., on the shrouds 930A/930B at the sides of thebelt 920. In embodiments, each color strip includes one or more LEDs ofappropriate color (red LED for a red strip, orange LED for orange strip,etc.). The placement of the color bands 992/993/994 and the color strips996/997/998 are “corresponding” in the sense that, for a user (thespecific user in the case the placements are user-adjustable, or anaverage user), appropriate placements of the vertical grips 999A/B andthe strips 1096/1097/1098 are indicated by the same color for a givenexercise level. In the shown embodiment, for example, yellow maycorrespond to walking, orange may correspond to jogging, and red maycorrespond to running. Thus, when the user intends to walk, he or shemay place vertical grips at the yellow bands 992A/B, and then place feetin the area between the yellow strips 998A/B; when the user intends tojog, he or she may place the vertical grips at the orange bands 993A/B,and then place feet in the area between the orange strips 997A/B; andwhen the user intends to run, he or she may place the vertical grips atthe red bands 994A/B, and then place feet in the area between the redstrips 996A/B.

The electronic monitor/controller module may include a display and maybe connected to sensor(s) (such as a speed sensor and/or a load sensorand/or a heart rate sensor), to provide information to the user of thetreadmill regarding the user's workout. The information may includespeed, distance, total caloric expenditure, current caloric burn rate,current heart rate, highest heart rate achieved during the workout, andother data.

The features described throughout this document may be presentindividually, or in any combination or permutation, except where thepresence or absence of specific elements/limitations is inherentlyrequired, explicitly indicated, or otherwise made clear from thecontext.

Not every illustrated element is necessarily required in everyembodiment in accordance with the concepts described in this document,while some elements that have not been specifically illustrated may bedesirable in some embodiments in accordance with the concepts.

This document describes in detail the inventive treadmills and rollerassemblies. This was done for illustration purposes and, therefore, theforegoing description is not necessarily intended to limit the spiritand scope of the invention(s) described. Neither the specificembodiments of the invention(s) as a whole, nor those of its (or their,as the case may be) features necessarily limit the general principlesunderlying the invention(s). The specific features described herein maybe used in some embodiments, but not in others, without departure fromthe spirit and scope of the invention(s) as set forth herein. Variousphysical arrangements of components and various step sequences also fallwithin the intended scope of the invention(s). Many additionalmodifications are intended in the foregoing disclosure, and it will beappreciated by those of ordinary skill in the pertinent art that in someinstances some features will be employed in the absence of acorresponding use of other features. The embodiments described above areillustrative and not necessarily limiting, although they or theirselected features may be limiting for some claims. The illustrativeexamples therefore do not necessarily define the metes and bounds of theinvention(s) and the legal protection afforded the invention(s).

What is claimed is:
 1. A treadmill comprising: a frame; a looped runningbelt; a first roller assembly comprising: a first roller tube, a firstrotating pulley and a second rotating pulley mounted on the first rollertube, a first shaft fixedly mounted on the frame and surrounded by thefirst roller tube, a first insert positioned on a first end of the firstshaft, the first insert having an external surface fixedly coupled to aninner surface of the first roller tube, the first insert having aninternal surface with at least a first diameter, a second diameter, anda third diameter such that first diameter is smallest and is positionedfurthest from the first end of the first shaft and the third diameter islargest and is positioned closest to the first end of the first shaft, asecond insert positioned on a second end of the first shaft, the secondinsert having an external surface fixedly coupled to an inner surface ofthe first roller tube, the second insert having an internal surface withat least the first diameter and the second diameter such that firstdiameter is positioned furthest from the second end of the first shaftand the second diameter is positioned closest to the second end of thefirst shaft, a first load bearing positioned on the first end of thefirst shaft, the first load bearing having an inner ring fixedly coupledto the first shaft and an outer ring fixedly coupled to the innersurface of the first insert having the second diameter to allow thefirst roller tube to freely rotate around the first shaft, a second loadbearing positioned on the second end of the first shaft, the second loadbearing having an inner ring fixedly coupled to the first shaft and anouter ring fixedly coupled to the inner surface of the second inserthaving the second diameter to allow the first roller tube to freelyrotate around the first shaft, and a one-way device positioned on thefirst end of the first shaft, the one-way device having an inner ringfixedly coupled to the first shaft and an outer ring fixedly coupled tothe inner surface of the first insert having the third diameter to allowthe first roller tube to rotate around the first shaft in a firstdirection and to prevent the first roller tube from rotating around thefirst shaft in a second direction that is opposite to the firstdirection; and a second roller assembly mounted on the frame, whereinthe looped running belt is supported by the first roller assembly andthe second roller assembly such that the first and second rotatingpulleys rotate with movement of the looped running belt.
 2. Thetreadmill according to claim 1 further comprising a first row thatcomprises a first plurality of supporting/guiding bearings interspersedwith a first plurality of guiding pulleys along a first longitudinalside of the frame, and a second row that comprises a second plurality ofsupporting/guiding bearings interspersed with a second plurality ofguiding pulleys along a second longitudinal side of the frame, the firstand second rows supporting the looped running belt.
 3. The treadmillaccording to claim 2, wherein inside surface of the looped running beltcomprises a first protrusion along a first side of the looped runningbelt that is proximate to the first longitudinal side of the frame, anda second protrusion along a second side of the looped running belt thatis proximate to the second longitudinal side of the frame, the firstprotrusion being dimensioned to fit into the first plurality of guidingpulleys, the second protrusion being dimensioned to fit into the secondplurality of guiding pulleys, whereby the first plurality ofsupporting/guiding bearings and the first plurality of guiding pulleyssupport a first side of the looped running belt and the second pluralityof supporting/guiding bearings and the second plurality of guidingpulleys support a second side of the looped running belt.
 4. Thetreadmill according to claim 1, wherein the second roller assemblycomprises: a third rotating pulley; a fourth rotating pulley; a secondshaft: fixedly mounted on the frame so that the second shaft does notrotate with the third and fourth rotating pulleys; a second roller tube,the third rotating pulley and the fourth rotating pulley being mountedon the second roller tube to rotate together with the second rollertube; and a third load bearing and a fourth load bearing disposedbetween the second roller tube and the second shaft, so that the secondroller tube and the third and fourth rotating pulleys can rotate aroundthe second shaft.
 5. The treadmill according to claim 1, wherein thefirst roller assembly or the second roller assembly further comprises anadditional one-way device configured to prevent a top surface of thelooped running belt from moving from a rear of the treadmill to a frontof the treadmill.
 6. The treadmill according to claim 1, wherein thefirst roller assembly is a front roller assembly so that the first shaftis mounted on the frame closer to the front of the treadmill than thesecond roller assembly.
 7. The treadmill according to claim 1, whereinthe first roller assembly is a real' roller assembly so that the firstshaft is mounted on the frame closer to a rear of the treadmill than thesecond roller assembly.
 8. The treadmill according to claim 1, whereinthe one-way device comprises a one-way clutch, the inner ring of theone-way device comprises portions defining; a keyway, and the firstshaft comprises a key configured to protrude into the keyway therebyfixing the inner ring of the one-way device to the first shaft.
 9. Thetreadmill according to claim 8, wherein the first insert and the secondinsert are made of metal, the first insert and the second inserts arepress-fitted into the first roller tube, the second Insert is shorterthan the first insert, and the first and second rotating pulleys aremade of injection molded plastic.
 10. The treadmill according to claim9, wherein the first shaft is fixed to the frame with a first bolt nearthe first end of the first shaft and with a second bolt near the secondend of the first shaft.
 11. The treadmill according to claim 1, whereinthe treadmill is motorless.
 12. The treadmill according to claim 1,wherein the treadmill is motorized.
 13. The treadmill according to claim1, further comprising a display, electronics, and one or more sensorsconfigured to provide information to a user of the treadmill regarding aworkout of the user.
 14. The treadmill according to claim 1, furthercomprising handlebars to allow a user to hold onto the treadmill whenexercising.
 15. The treadmill according to claim 1, wherein the loopedrunning belt comprises a multiplicity of interconnected slats.
 16. Thetreadmill according to claim 1, wherein the frame is configured so thata top surface of the looped running belt is curved to allow variation inexercise intensity.
 17. The treadmill according to claim 1, wherein theframe is configured so that a top surface of the looped running belt iscurved so that incline of the looped running belt varies by at least 20degrees from end to end.
 18. The treadmill according to claim 1, furthercomprising a raising bar attached to rear of the frame, and a pair ofwheels attached to front of the frame.
 19. The treadmill according toclaim 1, wherein the first and second directions are configured to allowa top surface of the looped running belt to move from a front of thetreadmill to a rear of the treadmill and to prevent the top surface ofthe looped running belt moving from the rear of the treadmill to thefront of the treadmill.
 20. A treadmill comprising: a frame; a loopedrunning belt; and a first roller assembly comprising a first rotatingpulley and a second rotating pulley, a second roller assembly comprisinga third rotating pulley and a fourth rotating pulley, the first rollerassembly and the second roller assembly being mounted on the frame, thelooped running belt being supported by the first rotating pulley, thesecond rotating pulley, the third rotating pulley, and the fourthrotating pulley, wherein the first roller assembly further comprisesmeans for allowing the first rotating pulley and the second rotatingpulley to rotate in a first direction to allow a top surface of thelooped running belt to move from front to rear of the treadmill and forpreventing the first rotating pulley and the second rotating pulley fromrotating in a second direction opposite the first direction that wouldallow the top surface of the looped running belt to move from rear tofront of the treadmill, and wherein the first roller assembly furthercomprises: a first roller tube, a first shaft surrounded by the firstroller tube and fixedly mounted on the frame, a first insert positionedon a first end of the first shaft, the first insert having an externalsurface fixedly coupled to an inner surface of the first roller tube,the first insert having an internal surface with at least a firstdiameter, a second diameter, and a third diameter such that firstdiameter is smallest and is positioned furthest from the first end ofthe first shaft and the third diameter is largest and is positionedclosest to the first end of the first shaft, a second insert positionedon a second end of the first shaft, the second insert having an externalsurface fixedly coupled to an inner surface of the first roller tube,the second insert having an internal surface with at least the firstdiameter and the second diameter such that first diameter is positionedfurthest from the second end of the first shaft and the second diameteris positioned closest to the second end of the first shaft, a first loadbearing positioned on the first end of the first shaft, the first loadbearing having an inner ring fixedly coupled to the first shaft and anouter ring fixedly coupled to the inner surface of the first inserthaving the second diameter to allow the first roller tube to freelyrotate around the first shaft, a second load bearing positioned on thesecond end of the first shaft, the second load bearing having an innerring fixedly coupled to the first shaft and an outer ring fixedlycoupled to the inner surface of the second insert having the seconddiameter to allow the first roller tube to freely rotate around thefirst shaft, and a one-way device positioned on the first end of thefirst shaft, the one-way device having an inner ring fixedly coupled tothe first shaft and an outer ring fixedly coupled to the inner surfaceof the first insert having the third diameter to allow the first rollertube to rotate around the first shaft in a first direction and toprevent the first roller tube from rotating around the first shaft in asecond direction that is opposite to the first direction.